<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>严格模式</title>
</head>
<body>
    <script>
        //严格模式，所有js代码都遵循严格模式
        'use strict'

        //局部严格模式.只在函数内部使用严格模式
        function fn1(){
            'use strict'
        }
        

    </script>
</body>
</html>